Fergie's relationship with her divisive former father-in-law hasn't improved in the intervening years, and it seems Prince Philip's opinion has affected younger members of the Windsor clan.
Prince William is also thought to have a "lack of warmth" for his former aunt, Town and Country Magazine reports.
Sarah was not invited to the Duke of Cambridge's wedding to Kate Middleton in 2011.
Yet the effervescent Fergie she has maintained a close relationship with Her Majesty Queen Elizabeth II, always said to have great affection for her son's ex-wife.
The Duchess of York reportedly stopped by the Queen's quarters every time she visited Buckingham Palace during her marriage to Andrew.
On the other hand, Prince Charles' first wife Princess Diana - a fourth cousin and on-again off-again friend of Fergie's until her death in France in 1997 - is said to have called to the Palace only to use Her Majesty's swimming pool.
Fergie also shares an incredible bond with her ex-husband, Prince Andrew, who are now thought to be more than just good friends.
The exes have lived together at the Royal Lodge since 2008, and went on holiday to Bahrain with their daughter Princess Beatrice earlier this year.
They also take regular trips to the upscale Swiss ski resort of Verbier together.
After Prince Philip's retirement from royal duty in 2017, the Duchess of York has slowly but surely made her way back into the Windsor fold, attending a litany of royal family events including the preview of Trooping the Colour and the wedding of Lady Gabriella Windsor in London last month.
Fergie was also invited to the royal wedding of her former nephew Prince Harry to American-born actress Meghan Markle in St George's Chapel at Windsor Castle last year.
But it was her iconic appearance at her own daughter Eugenie's wedding to Jack Brooksbank six months later that cemented the Duchess of York's re-entry into the royal family fold.
Last week, the Duke of York brought his ex-wife into the Royal Box to chat with the Queen at Royal Ascot, something Andrew is unlikely to have done if the Duke of Edinburgh had been present.